Process of making a decolorizing clay



Nov. l1, 1930. w. s. BAYLls 1,781,255

PROCESS OF MAKING A DECOLORIZING CLAY Filed May 14, 1929 A TTORNE f.

Patented Nov. 11, 1930 UNITED STATES PATENT oFFlcE WALTEB-S. IBA'YLIS,OF LOS ANGELES, CALIFORNIA, ASSIGNOR TO FILTBOL COMPANY F CALIFORNIA, OFLOS ANGELES, CALIFORNIA, A CORPORATION `OIE* CALIFORNIA PROCESS OFMAKING A DECOLORIZING CLAY Application led May 14,

This invention relates to the activation of clays with mineral acids,such as diluted or concentrated sulfuric, hydrochloric, or nitric acids.This application is a continuation-inpart of m co-pending application,Serial No. 110,962, led May 22, 1926. The invention herein described isintended to be an improvement on the process and productl disclosed inU. S. Patent No. 1,492,184 to J. W.

Weir and J. C. Black. In that patent colloidal clays of various kindsare treated with about ten ercent. of their weightof concentrated suluric acid without washing out the reaction products of the acid and theclay,

nor driving off the Water of crystallization from the clay, noreliminating the excess acid, if any.` Theoretically, the acidity shouldbe entirely neutralized in this roduct by the excess of clay in themixture ut, practically,

several difficulties have been encountered with the product. At timesshipments of the clay have eaten holes in the cloth or paper bags inwhich the material was ship ed and the high free acidity has had a bad eect upon the hands and shoes of workmen hancium magnesium aluminumsilicate types (of which smectite, including bentonite, montmorillonite,fullers earth and the like, are typical) aretreated b adding to themfrom 25% to 50% by weig t of any of the acids above mentioned, butpreferably sulfuric acid; the cla and acids are then thoroughly mixedand t en from three to five times the weight of raw` clay is added tothe mixture as was used in the original batch which was acid treated.The underlying thought of this procedure is tc. first uniformlydistribute the treatin acid in a small batch of clay and then a dsufficient raw clay to substantially 4 neutralize the excess of acid.The treated clay andthe raw clay are to be well mixed so that asubstantially uniform distribution of acid occurs. The mixed mass isthen allowed to react for a suitable length of time, say from one hourto twenty-four hours, so as to get the full benefit of the strength of1929. Serial No. 363,043.

as the acid anhydride. This tem erature is intended to be onlysutlicient to vo atilize the remaining excess acidbut not sufiicient tosmter or glaze the clay particles. If hydrochloric or nitric acids areused, the temperature may be sufficient to partly or wholly decomposesome of the nitrates or chlorides present, but their completedecomposition or volatilization is not necessary. The temperature shouldbe sulcietly high to drive off a substantial quantity, preferably themajor part of the water of crystallization in the clay. I have foundthat such water-free clay gives better results upon certain oils thancan be had from a product, such as ,that of Weir and Black which stillretains it.l

Specifically, I may use an acid ranging from 15% to 35% in strength in aproportion o f from 25% to 5.0% by weight upon an initial batch of clay,which shall be from 20% to 33% of the totalweight of the entire claybatch. The acid-treated clay batch may then be dehydrated andde-acidlfied at temperatures ranging from 300 F. to 750 F., thetemperature being held as low as possible to accomplish the desiredresult upon the specific cla and acid combination used. p suitableprocedure and apparatus for carrying out my process is shown in theaccompanymg drawing, in which there is rovided` a solution tank l, anagitator 2, a lter press 3, a dry mixer 4 and a dehydrator 5.

The solutlon tank 1 consists of a shell 11 having a conical bottom 12 towhich a pipe 13 is connected, thispi e 13 having a valve 14 l whichagitating paddles 24 are carried. The

shaft 23 is rotated by beveled gears25. The solution of sulfuric acid isintroduced into the Aagitating chamber 22v throu h the pipe 13b when thevalve 14ris open.. aw clay is initr'oduced into the chamber 23 through al s out 26. Sulfuric acidand vraw clay are'l oroughly mixed in the aitating'chamber 22, it being desirable to have a m1xture of acid and rawclay which contains from 25% to 50% by weight of sulfuric acid, dueallow# ance being made for anyI Water initially in the .cla The acid andclay7 react on'each -other uring the time that they are mixed, 5 and itis found that this reaction is highly promoted, most likely since alarge quantity of sulfuric acid vis mixed with a comparatively 25 .press3. The p1pe 2 8 `is joined Ato a shell 32' A clay 'small quantity of rawclay. The raw`clay' lwhen-it has been thoroughly acted upon vby thesulfuric acid forms what I'term treated Extendin from the bottom of theshell 21 is a pipe 28 aving avalve 29 and a 31 therein. "This pipe 28extends to the lter I of the filter press 3 and is incommunication i' Lwith a lter chamber-33 which is provided by the shell 32. in. thechamber33 isa plurality my of filter bags 34, made preferably of Wool orasbestos, the interior of which have pipes 35 connected therewith'.These pipes 35 connect with a header 38 having a vacuum pump 37 therein.After the clay and sulfuric acid are thoroughly mixed, the valve29 inthe pipe .28 is opened and the pump 31 is set into operation so that themixture will be forcedto the filter press 3. The filter ,bags 34 arefabril cated so that only the liquid of the mixture may passtherethrough and through the pipe 35'l1nto the header 36. Therefore, theacid treated clay will collect in cakes'38 onthe bags `34. The lvacuumpump 37 may be set into operation at the Sametime that the pump veyor42.

31 is set into operation. After all themixture has been pumped throughthe lterpress 3 the vacuum 'ump will effectively draw most of the freellquid from the cakes of treated clay 38, leaving them nearly dry.

The treated 'clay is then removed from the `lter press 3 and dumped intoa hopper 41. The'treated clay is 'delivered from the hopper 41 to thedry mixer 4 by means of a con- The dry ixer 4' consists of a shell' 43pro- .viding a mixing chamber 44. Paddlesl 45 are secured on a shaft 46in the chamber 44, this shaft being drivenl by bevel gears 47'.l Raw,

lpasse to thedehydrator 5.

mix the treated clay and the raw clay, the mixin action is arrested andthe mixture is The bottom of the shel1'43 of the dry mixer 4 isconnectedl to the conveyor. 49 through a valve 51. The valve 51 isopened and the conveyor 4 9 is set into operation, thus taking themixture from the mixer 4 and delivering it to the dehydrator 5. Thedehydrator 5 is shown as being av kiln and consists of a drum 53 v whichis rotatably supported on rollers 54 and which is rotated lby a gear 56which meshes with a gear 57 of the drum 53. The'interior of the drum 53is very highly heated and the mixture is passed therethrough from theleft end to the right 'end thereof.' 1n the dehydrator the mixture isheated in order to drive off unreacted acid, as anhydride, and to driveoff the water of crystallization. The mixture passes from the dehydrator5, through a conduit 59, inthe form of decolorizing clay ofsubstantially neutral or perhaps feebly acidV reaction.

. It should befclearly understood that in the drawing I diagrammaticallyillustrate apparatus for conducting my process to produce thedecolorizing clay'of my invention, and it should alsobe understood thatother apparatus for accomplishing the same results might be used. Forexample, different forms of agitators' and, mixers might'beused anddifferent forms of apparatus for drying the treated clay and fordehydrating the mixture of treated clay and raw clay mightv be used. Forinstance, in place of the iilter press 3 the liquid might be separatedfrom the treated -clay by decantation.

The decolorizingclay of my invention is of high quality and is a veryetlicient decoloriz- "ing agent for oils. Also, the decolorzing clayofgmy invention. is very cheaply produced.,4 i

As a modification of the above described method, I may mix untreatedclay with the first' batch of acid-containing claywithout firstseparating excess acid from the first batch with a filter press orotherwise. The excess acid may then be driven 0E by heat as before. y

I claim as m'y invention:

1. The'process which'comprises treating an initial batch of anactivatable colloidal clay with a highly ionized mineral acid; adding aa greater quantity of raw activatable clay; and subjectin the mixture-toa temperature sufficient tov e iminate substantially all water ofcrystallization and free acid from the clay.

2. A process according to claim 1 in which the clay is ofthe activatablebentonite typeand in which lthe acid is sulfuric acid. 3. 'The processwhich comprises: treating an initial ybatchy of an-activatable colloidalclay with la 'highlyl ionized mineral acid of from.15%to35% strength;then' adding a substantial quantityof untreated clay of the menacsV samekind allowing the reaction to become substantially complete; and thensubstantially eliminating water of crystallization and free acid fromthe mixture.

4. A process accordin to claim 3 in which the adsorbent is derive from aclay of the activatable bentonite type and the ac1d is su1- furie acid.

5. The process which comprises: treating an initial batch of anactivatable colloidal clay with a highly ionized mineral acid of from15% to 35% strength; then adding raw clay of the same kind in quantityfrom three to five times the weight of the initial batch; allowing timefor the reaction between acid and clay to become substantially complete;and then substantially eliminating free acid and Water ofcrystallization from the mixture by heating to a temperature between-300 F. and 750 F.

6. A process according to claim 5 in which the acid is sulfuric acid andthe clay is of the activatable bentonite type.

7. A process according to claim 5 in which the weight of acid added tothe rst clay batch ranges from 25%'130 50% of said clay batch.

8. An activated adsorbent clay retaining substantial quantities of thesalts formed during the activating treatment, but being devoid ofsubstantial free acidity and water of crystallization.

9. An adsorbent of the kind described in claim 8 in which the clay fromwhich the adsorbent is made is derived from an activatable bentonite.

In testimony whereof, I have hereunto set my hand at New York, New York,this 13th day of May, 1929.,

v WALTER S. BAYLIS.

